Downlink control information transmitting method and base station, and downlink control information receiving method and user device

Abstract

In the transmission of user data for a user equipment and control information on the user data to the user equipment using a plurality of carrier waves by a base station in a wireless communication system, the control information can be transmitted over a portion of the plurality of carrier waves, and carrier waves over which only the user data is transmitted can be generated without the control information. Here, the base station transmits, at a certain number of subframes following the subframes at which the control information is transmitted, the user data over the carrier waves to which only the user data is allocated. Thus, the user equipment can minimize the buffering of the user data during the detection of the control information, and decode the user data.

What is claimed is:  
     
       1. A method for transmitting, by a base station, downlink control information to a user equipment using a plurality of carriers in a wireless communication system, the method comprises:
 transmitting a first physical downlink control channel (PDCCH) carrying first control information, which is for transmission of a first physical downlink shared channel (PDSCH) and includes a carrier indication field set to indicate a first carrier among the plurality of carriers, and a second PDCCH carrying second control information, which is for transmission of a second PDSCH and includes a carrier indication field set to indicate a second carrier among the plurality of carriers, through the first carrier to the user equipment in a subframe n; 
 transmitting the first PDSCH carrying first downlink data through the first carrier based on the first control information to the user equipment in the subframe n; and 
 transmitting the second PDSCH carrying second downlink data through the second carrier based on the second control information to the user equipment in a subframe n+k when the second carrier is different from the first carrier and carries no PDCCH, 
 wherein k is equal to 1or 2, and 
 wherein the subframe n and the subframe n+k are downlink subframes. 
 
     
     
       2. The method of  claim 1 , further comprising:
 transmitting information indicating k to the user equipment. 
 
     
     
       3. The method of  claim 2 , wherein the second PDCCH carries the information indicating k. 
     
     
       4. A method of receiving, by a user equipment using a plurality of carriers, downlink control information in a wireless communication system, the method comprises:
 receiving, by the user equipment, a first physical downlink control channel (PDCCH) carrying first control information, which is for reception of a first physical downlink shared channel (PDSCH) and includes a carrier indication field set to indicate a first carrier among the plurality of carriers, and a second PDCCH carrying second control information, which is for reception of a second PDSCH and includes a carrier indication field set to indicate a second carrier among the plurality of carriers, through the first carrier in a subframe n; 
 receiving, by the user equipment, the first PDSCH carrying first downlink data through the first carrier based on the first control information in the subframe n; and 
 receiving, by the user equipment, the second PDSCH carrying second downlink data through the second carrier based on the second control information in a subframe n+k when the second carrier is different from the first carrier and carries no PDCCH, 
 wherein k is equal to 1or 2, and 
 wherein the subframe n and the subframe n+k are downlink subframes. 
 
     
     
       5. The method of  claim 4 , further comprising:
 receiving information indicating k from the base station. 
 
     
     
       6. The method of  claim 5 , wherein the second PDCCH carries the information indicating k. 
     
     
       7. A base station of transmitting downlink control information to a user equipment using a plurality of carriers in a wireless communication system, the base station comprises:
 a transmitter configured to transmit radio signals through the plurality of carriers; and 
 a processor, connected to the transmitter, configured to control the transmitter to transmit a first physical downlink control channel (PDCCH) carrying first control information, which is for transmission of a first physical downlink shared channel (PDSCH) and includes a carrier indication field set to indicate a first carrier among the plurality of carriers, and a second PDCCH carrying second control information, which is for transmission of a second PDSCH and includes a carrier indication field set to indicate a second carrier among the plurality of carriers, through the first carrier to the user equipment in a subframe n; to transmit the first PDSCH carrying first downlink data through the first carrier based on the first control information to the user equipment in the subframe n; and to transmit the second PDSCH carrying second downlink data through the second carrier based on the second control information to the user equipment in a subframe n+k when the second carrier is different from the first carrier and carries no PDCCH, 
 wherein k is equal to 1or 2, and 
 wherein the subframe n and the subframe n+k are downlink subframes. 
 
     
     
       8. The base station of  claim 7 , wherein the processor is configured to control the transmitter to transmit information indicating k to the user equipment. 
     
     
       9. The base station of  claim 8 , wherein the second PDCCH carries the information indicating k. 
     
     
       10. A user equipment, using a plurality of carriers, of receiving downlink control information in a wireless communication system, the user equipment comprises:
 a receiver configured to receive radio signals through the plurality of carriers; and 
 a processor configured to control the receiver to receive a first physical downlink control channel (PDCCH) carrying first control information, which is for reception of a first physical downlink shared channel (PDSCH) and includes a carrier indication field set to indicate a first carrier among the plurality of carriers, and a second PDCCH carrying second control information, which is for reception of a second PDSCH and includes a carrier indication field set to indicate a second carrier among the plurality of carriers, through the first carrier in a subframe n; to receive the first PDSCH carrying first downlink data through the first carrier based on the first control information in the subframe n; and to receive the second PDSCH carrying second downlink data through the second carrier based on the second control information in a subframe n+k when the second carrier is different from the first carrier and carries no PDCCH, 
 wherein k is equal to 1or 2, and 
 wherein the subframe n and the subframe n+k are downlink subframes. 
 
     
     
       11. The user equipment of  claim 10 , wherein the processor is configured to control the receiver to further receive information indicating k from the base station. 
     
     
       12. The user equipment of  claim 11 , wherein the second PDCCH carries the information indicating k.